1. Field of the Disclosure
The present disclosure relates to an electrophoretic display apparatus, a method for driving the same, and a method for measuring image stability thereof.
2. Discussion of the Related Art
An electrophoretic display apparatus is one of the flat panel display devices mainly used for manufacturing an e-book.
The electrophoretic display apparatus includes two electrodes facing each other, and an electrophoretic dispersion disposed therebetween. In a microcapsule type, a plurality of microcapsules containing an electrophoretic dispersion therein form a layer between the two electrodes. In a microcup type, an electrophoretic dispersion is divided by partition walls which define a plurality of pixels. Colored charged particles included in the electrophoretic dispersion move to an electrode of an opposite polarity through electrophoresis if an electric field is applied between the two electrodes, whereby an image can be displayed.
Since the electrophoretic display apparatus has bistability, the original image can be maintained for a long time even after the electric field applied between the electrodes is removed. In other words, the electrophoretic display apparatus can maintain a certain image for a long time although a voltage is not continuously provided thereto. Accordingly, the electrophoretic display apparatus is suitable for the applications that do not require a quick image switching.
On the other hand, due to such bistability, impulse required to change a gray scale of a certain cell for an image switching depends on the current gray scale, the next gray scale, and the time for which the current gray scale has been maintained as well. This dependency requires each cell to be refreshed before it is updated for the image switching. Refreshing of the cells causes flickering of the screen during the image switching and thus causes additional power consumption.
Meanwhile, in spite of the bistability, as a certain length of time passes, the charged particles in the electrophoretic dispersion might slightly move due to their electrical interaction and the gravity whereby causing a certain degree of gray scale transition which has never been wanted. Among the important factors that determine the performance of the electrophoretic display apparatus is how long an image can be stably maintained after the electrical field between the electrodes is removed. Nonetheless, a proper method for measuring the image stability of an electrophoretic display apparatus has not been suggested yet.